Electric switch



- Feb. 11, 1941. J. L. sHRoYER ELECTRIC SWITCH Filed Jan. 22, 1937 lll/ll,

Inventor: 57

lla

APatented Feb. 11, 1941 2,231,598

UNITED STATES PATENT OFFICE ELECTRIC SWITCH Jacob L. Shroyer, Oak Park, Ill.,- assignor to Edison General Electric Appliance Company, Chicago, Ill., a corporation of New York Application January 22, 1937, Serial No. 121,834

8 Claims. (Cl. 200-4) This invention relates to electric switches, and shown, is relatively massive in proportion. The it has for its object the provision oi an improved end wall IZa of the inner casing member conswitch of this character. stitutes the rear end 'of the casing I0, that is, of

This invention' has particular application to the switch. 5 multiple-position electric switches, such as used Mounted in the side of the front wall Ila of 5 in the control of the inter-connected circuits for the outer casing are a plurality of circuit cona heating system having a plurality of heating trolling contacts I3, I3a, |31) and |30 arranged in resistances to connect the resistances in different an arc of a circle and spaced at intervals along ways to give different degrees of heat. The inthe arc, Aas shown diagrammatically in Figs. 7-10.

i vention contemplates a. switch of this character Contacts I3, I3a, I3b and I3c are mounted on l0V which is safer in its operation, improved in its contact blades or leads I4, Illa, |413 and I4c reelectrical and mechanical characteristics, and one spectively. The leads, as shown, t into recesses l which is less expensive to make and which has a I provided for them in the inner surface of the longer life than those heretofore generally used. outer casing member II and extend from the l5 For a more complete understanding of this ln.- rear to the front of the switch where they have l5 vention, reference should be had to the accorn- 'portions turned inwardly at right angles to the panying drawing in which Fig. 1 is a vertical main body of the leads,'as clearly shown in Figs. sectional view illustrating a multiple-position 1 and 4.` These latter portions are received in electric switch arranged in accordance with this recesses i6 provided in the inner surface of the 2G inventin; Fig. 2 is a front elevation of the switch front wall IIa of the outer casing member. It 20 of Fig. l; Fig. 3 is a rea-r elevation of the'switch will be observed that when the inner casing memoi Fig. 1, parts being broken away so as to illuslber I2 is inserted in the outer member II, the trate certain details of construction; Fig. 4 is a Walls of the inner casing cooperate with those of sectional view similar to Fig. 1 but showing the the outer casing tohouse the leads in closed chanswitch ina different operative position; Fig. 5 nels so as to hold them rigidly in place in the 25 is a sectional view taken through the line 5--5 switch casing. The contacts I3, I3-a, I3?)` and I3c of Fig. 4 and looking in the direction of the armay be secured to their respective lead members rows; Fig. 6 is a sectional view taken through the in any suitable manner, as by welding, and the line 6-6 of Fig. 5 and looking in the direction of contacts may be formed of any suitable matethe arrows; Figs. '7, 8, 9 and 10 are diagrammatic rial, such as silver. The outer ends of the leads 30 views illustrating the electric switch of this inare provided with binding screws Ilia by means of vention applied to control the inter-connected which the external connections are made. circuits of an electric heating system involving Cooperating with the stationary contacts two resistance heating elements; and Fig. 11 is I3-I3c are a plurality of movable contacts II.

a sectional view of a. line switch arranged in The movable contacts I'I are mounted in a con- 35 accordance with this invention. tact carrier I8 which is of disc form and which Referring more particularly lto Figs. 1 to 10, has an outer diameter substantially equal to the this invention has been shown in one form as inner diameter of the inner casing member I2. applied to an electric'switch intended to control The contacts I1 are mounted on the side of the 40 the resistances of an electric heating system so disc facing the stationary contacts I3-I3c and, 4G as to connect them in different ways to give dilferas shown diagrammatically in Figs. '7-10, are arent degrees of heat such as high, low and medium ranged in a circle and spaced from each other heats. circumferentially.

As shown in the drawing, the electric switch The contacts I1 are mounted in recesses I9 comprises an electrically insulating casing I0. provided for them in the side or the disc. As 45 The casing I0, as shown, comprises two cupshown (Fig. 6), e'ach contact I`I is relatively elonshaped members II and i2 positioned in the regated and has inturned ends I'la arranged subverse order. The casing member. I2 is smaller stantially at right angles to the main body of than the casing member II and is inserted in it, the contact. These inturned ends are received as shown in Figs. l and 4. The casing members in relatively deep end sections provided in the 5c II and I2 are formed of a suitablemechanically recesses I9. A pair of helical compression springs strong, electrically insulating material, such as a 20 are inserted in recesses 2l back of each consuitable phenol condensation product. The front tact, and bear directly on the contact to force it wall I la of the outerk casing member II constioutwardly toward the front wall of the switch.

tutes the front of the switch. and this wall, as The carrier disc I8 is mounted on a shaft or 55 rod 22. It has a key-connection 23 with the shaft whereby the shaft is connected to rotate the disc, but can be slid freely axially relative to the disc.

Mounted-on the inner surface of the rear wall I2a of the casing I2 opposite the stationary circuit contacts I3-I3c are a pair of stationary spaced line contacts 24. As shown, these members are of relatively massive proportions, and are secured to the casing of the switch by molding them in the insulating material of which the inner casing I2 is made. The contacts 24 extend through the wall I2a and on the outside of this wall are provided with suitable binding screws 25 threaded in them. One contact 24, the righthand oneas viewed in Fig. 3, is electrically oonnected with the stationary contact I3c by means of the lead I4c and a connector 25a.

Cooperating with the line contacts 24 is a bridging Contact member 26. This member is arranged to abut the stationary line contacts 24 to complete the circuit through 'themi The bridging contact, as shown, is of disc form having a relatively large diameter, and it is connected to similarly shaped insulating supporting members 21 by means of rivets 28. The assembly of the bridging contact and supporting members is mounted directly on the end of shaft; 22 which is peaned or riveted over, as clearly shown in Fig. 1, to secure the assembly.

Interposed between this assembly and the contact carrying disc I8 is a compression spring 29 having one end bearing on the assembly and its inner end received in and bearing on the bottom of a recess 33 provided in the adjacent side of the disc. This spring, it will be observed, biases the rod axially inwardly of the switch to cause the bridging contact 26 to abut the line contacts, and biases the carrier I8 outwardly 'toward the front of the switch against the front wall of the housing.

It will be observed that the rod 22 constitutes a common operating member both for the contact carrying disc I8 and for the bridging contact 261. It operates the former through the key-connection 23 when it is rotated, and the latter when it is moved axially. The front end of the rod protrudes through the front wall of the casing, and on the exposed portion there is mounted an operating knob 3I which may be grasped to rotate the rod or move it axially.

It is important that the bridging contact 26 be moved to break the line contacts 24 before the position of the disc I8 is changed. In other words, it is important that the knob 3| be pulled forwardly to break the line contacts before turning the disc I8 to change the controlled circuit connections. I insure this operation by providing an interlock between the lrod 22 and the switch housing. This interlock comprises a cylindrical metallic member 32 mounted in a recess 33 provided for it in the front wall I Ia of the outer casing member, as shown in Figs. 1, 4 and 5. This member, as shown, is provided with a centrally arranged aperture receiving the rod 22. On the outer face of this memberv are provided a series of slot-like depressions 34 arranged at proper intervals circumferentially of the central opening corresponding to the 01T and circuit controlling positions of the switch. Arranged to be fitted into these slots is a key 35 iixed on the rod 22. Ihe slots are of such depth that whenthe knob is in the off position, that is, is in a position where the switch does not connect the controlled circuits with the line, it is held in its position shown in Fig. l wherein the line contacts 24 are open, but when it is in any of its circuit controlling positions, it can be moved inward sufficiently far to close the line contacts 24. However, before the switch can be moved from the oil to any controlling position, or from any one of these to another or to the oil position, it is necessary to pull the knob 3l forwardly to remove the key 35 from the slot in which it is in, whereupon the knob can be turned to another position.

In Figs. 7 to l0 inclusive, the switch has been shown as applied to a heating circuit having a pair of resistance heating elements 36 and 31. These resistance elements are energized from a two-wire source of supply having two supply conductors 38 and 39. In this particular system, the line wire 38 is connected with the lead member I4a and hence, with the stationary contact I3a, while the other line wire 39 is connected with one of the line contacts 24, the left-hand one, as viewed in Figs. 3 and 7 to 10. The opposite line contact is connected with the stationary contact I3c, as previously pointed out, and

also with one end of the resistance heating element 31, which is connected to lead I 4c. The other end of this resistance heating element, as well as one end of the resistance element 36, are connected directly with lthe stationary contact I3 through the lead I4. The other end of the resistance element 36 is connected with the stationary contact |317 through the lead I4b.

In the operation of the switch as applied to this system, it will be understood that in the off position, the parts are as shown in Fig. 7. Here the line is broken at the two contacts 24, because as previously explained the bridging contact 26 is held away from them by the interlock between the rod 22 and the Switch housing. Moreover, the stationary contact -I3a connected with the line 38 is disconnected from any of the circuit controlling contacts I3-I3c.

When the knob 3I is pulled forwardly and moved from its off position of Fig.'7 a quarter ,turn in a clockwise direction, as viewed in Fig. 2,

to its position of Fig. 8, the movable contacts I1 are turned to their positions shown in this ngure, and also, as previously described, when the knob 3I is released in this position of the knob, the spring 29 moves the rod 22 axially to close the line contacts 24. This operation of the switch connects the resistances 36 and 31 in parallel across the supply source, and effects high heat.

To effect a medium heat the switch is moved a quarter turn from its position of Fig. '8 to its position of Fig. 9. As before, it is necessary to pull the knob 3I forwardly to break the line contacts 24 before it can be rotated to its medium" position, and to release it in this position to close the line circuit. In this position, it will be observed, that the resistance conductor 31 onlyl is connected to the supply source.

To provide low heat the knob 3I is pulled outwardly and moved a quarter turn to the position designated low. Fig. l0 shows the circuits in this position; as here shown, the two resistance elements 36 and 31 are connected in series across the supply lines 38 and 39.

In order to conveniently mount the switch housing in a suitable supporting panel 40, such as in the front wall of the switch panel of an electric range, the panel is provided with a cylindrical aperture 4I having adiameter substantially equal to the outer diameter of the outer acentos casing member il. 'Ihiicasingimember isprovided with an outwardly extending flange 42 about the front wall ila arranged to abut against the iront wall of the panel, as shown in Figs. 1

and 5. Arranged back of this flange and spaced' from it a distance Asubstantially equal to the -thickness of the panel I0 are a plurality of peripherally spaced lugs 43. These lugs are arranged to be insertedthrough notches M spaced about the opening Il and positioned with relation to each other as are the lugs 4I, but angularly removed as a system from the system of lugs when the switch housing is in its normal operative position shown in Figs. 1 and 4. The switch housing is applied to the panel by inserting it through the opening Il so that the lugs I3 pass through the notches ll, and then by rotating the switch to its proper operative position. In this position, the switch housing is locked against axial movement relative to the panel by the ilange l2 and lugs Il which sandwich the panel between them. It is locked against rotary movement in thepanel by means of a spring latch 45. 'I'his latch, as shown, is mounted in a recess 4l provided in the bottom of the switch housing and is secured to the housing by means of rivets I1. The latch, as shown, protrudes from the recess, and when the switch housing is rotated to its normal operative position after being mounted in the panel springs into a notch 48 provided for it in the panel. The latch is forced into the recess 46 when the housing is applied to the panel and while being rotated to its normal operative position.

A very important feature of this invention is the arrangement of the insulating disc Il between the stationary contacts il--i3c and their associated movable contacts i1, and the cooperating line contacts 24 and 26. The disc il in eiIect divides the switch housing into two electrically insulating chambers in which these two sets of contacts are housed respectively.

Another very important feature is that there is only one set of contacts, namely, the bridging contact 28 and spaced stationary contacts 24, which actually make and break the live line circuit.

A further important feature is that the bridging contact 26 makes butt contact with the line contacts 24, rather than a sliding contact, and also that these contacts are relatively large and massive. These features are oi' material importance where large wattages are encountered, such as those found in electric ranges and heavy duty heating equipment. Here the wattages may be for example two to four thousand and in some instances many more, and the voltages as high as 250; They are important because they do not permit an arc to be drawn out from the line contacts when the circuit is broken having suilicient energy to detrimentally aiect the contacts. On the contrary, the energy oi.' any arc that might be formed is negligible. And this is true whether the knob be pulled out slowly or quickly, because the length of the arc that can be formed is denitely limited. The len'gth of the arc, and there'- iore the energy generated in the arc is deilnltely limited by limiting the distance that the bridging contact can be separated from the contacts 24. It vwill be observed that this distance'is determined by the key 35 engaging the iront wall of the switch in the outward movement of the knob il. The distance that the key, and hence the contact 26, can be moved outwardly is such that even though the knob 3i be drawn outwardly at "an unusually rapid rate, and an arc thereby set up, the arc will be so short that the energy developed in it is not great enough to burn or pit the contacts. 'Ihe distance that the contact 26 is moved outwardly need only be from I of an inch to of an inch for voltages as high as 250. I have discovered that this very short butt break of the large massive contacts 24 disrupts the circuit with practically no deteriorating arcing energy.l This, o! course, materially increases the life of the switch.

Moreover, the operating parts of the switch mechanism are fully enclosed in the housing Il, which excludes dust and dirt from the mechanism. No lubrication for the moving parts is re- Cil quired. There are no sliding live contacts. In y addition, the switch formed as it is of simple parts has a very low manufacturing cost. Furthermore, each switch can be readily applied to and removed from lits control panel independently of the rest by a simple mechanical operation:

Certainl of the advantageous characteristics oi! this invention referred to above may also be used in a single pole switchiy Such a switch is shown ln Fig. l1. 'I'his switch comprises a cup-shaped casing 50 having its end closed by a wall 5I. Mounted in this wall are a pair of relatively large massive spaced contacts 52. Cooperating with these contacts is a large disc-shaped bridging contact 53. This contact is mounted on an operating rod 5I mounted for axial movement in the front wall of the casing 55, as shown. 'I'he bridging contact is biased to engage the spaced contacts 52 by means of a compression spring 55. The rod 54 carries a key 56 received in a slot 51 in the front wall oi the casing. The switch may be moved from its open or oil. position by moving the Vrod 54 forwardly until the key clears the passageway 51, whereupon the rod may be turned to cause the key to engage an outer portion of the front wall to hold the rod in its withdrawn or open position against the bias of the spring 55. The outer end of the rod is provided with a knob 58 whereby it may be conveniently operated. Here the contacts are relatively massive, as in the rst case, and here also, the contacts are made and broken by a relatively slow movement. InA addition to this, the distance that the bridging contact 53 can be moved away from the xed contacts 52 is definitely limited by an extension 59 provided on the iront wall of the casing.

While I have shown particular embodiments of my invention, it will be understood, oi' course, that I do not 'wish to be limited thereto s ince many modications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States iszl. A switch comprising a housing, a contact supporting member between the ends of said housing dividing it into two aligned chambers, a plurality of spaced contacts in one of said chambers, contacts on said supporting member moved into and out oi' engagement with said stationary contacts by rotation of the supporting member, an operating member connected to said supporting member to rotate it to move the contacts thereon into engagement with said stationary contacts and having sliding movement axially of said supporting member, a pair of coritacts in the other of said chambers, and a bridging contact carried by said supporting member movable into and out of abutting relation With said pair of contacts by axial movement of said member.

2. A switch comprising an electrically insulating enclosed cylindrical casing, an insulating disc mounted in said casing having a diameter substantially equal to the internal diameter of said casing, a rod connected to said disc arranged to rotate it in said casing and having free sliding movement axially of said disc, a plurality of spaced circuit contacts mounted in an end wall of said casing, contacts on said disc facing said circuit contacts and arranged to selectively engage them by rotation of said disc, a spring on said rod biasing said disc toward said one end wall, a plurality of line contacts in the opposite end wall on the other side of said disc, and a bridging contact carried by said rod and movable into and out of abutting relation with said line contacts by axial movement of said rod.

3. A switch comprising an electrically insulating enclosed cylindrical casing, an insulating disc mounted in said casing between its ends dividing the casing into two chambers substantially separated from each other electrically, a rod connected to said disc arranged to rotate it in said casing and having free sliding movement axially of said disc, a plurality of spaced-circuit contacts mounted in one end wall of said casing in one of said chambers, contacts on said disc facing said circuit contacts and arranged to selectively engage them by rotation o said disc, a plurality of line contacts in the opposite end wall in the other of said chambers, and a bridging contact in the latter chamber on the end of said lrod movable into and out of abutting relation with said line contacts by axial movement of said rod, a spring on said rod between said bridging contact and said disc biasing the disc toward said one end of said casing and permitting movement of said rod axially of the disc to carry said bridging contact into and out of abutting relation with said line-contacts while holding said disc against said one end.

4. An electric switch comprising a casing, circuit contacts in said casing, a contact-carrying member in said casing having contacts thereon arranged to engage said circuit contacts selectively when said member is rotated, a rod arranged to rotate said member from an oil to a plurality ol circuit closing positions, but freely slidable axially relative to said member, line contacts in said casing, a contact operated by said rod into and out of engagement with said line contacts by axial movement of said rod, a spring biasing said rod axially to cause said contact t0 engage said line contacts, and interlocking means between said rod and said casing arranged to hold the rod from rotating when in each of said 01T and circuit-closing positions and holding saidv rod against axial movement by said spring to close said line contacts when the rod is in the 01T position.

5. An electric switch comprising a casing, circuit contacts in said casing, a contact-carrying member in said casing having contacts thereon arranged to engage said circuit contacts selectively when said member is rotated, a rod arranged to rotate said member from an off to a plurality of circuit closing positions, but freely slidable axially relative to said member, line contacts in said casing, a contact on said rod movable into and out of engagement with said line contacts by axial movement of said rod, a spring biasing said rod axially to cause said contact to engage said line contacts, a member surrounding said rod, a pin on said rod, a plurality of spaced slots in said member corresponding to the olf and circuit controlling positions of said rod arranged to receive said pin in the various controlling positions of said rod to hold the rod from turning, the slot corresponding to the ofi pcs# tion being of such depth as to hold the rod axially in such positions that said contact on said rod is held out of engagement with said line contacts, and the remaining slots being suftlciently deep to permit said rod to move to close said line contacts.

6. A switch comprising an electrically insulating housing having side walls and a wall closing the housing at one end, contacts mounted in said wall at the end, leads lor said contacts extending from said contacts to the opposite end of said side walls and the side walls having longitudinally extending channels that receive said leads, and a closing cup-shaped sleeve formed of an electrically insulating material inserted in said casing closing said opposite end and cooperating with said channels to enclose and secure said leads.

7. In a switch, a cup-shaped electrically insulating casing having a plurality of longitudinally extending peripherally spaced recesses in the side wall terminating in recesses substantially at right angles thereto in the end wall, a plurality of contact leads in said recesses in said side wall, and having portions at right angles thereto fitted in said recesses in the end wall, a second cup-shaped electrically insulating member inserted in the first member in close tting relation with the Walls thereof so as to close said recesses, and so that its inner edge engages the portions of said leads in the end wall of said first member, and contacts secured to said portions.

8. An electric switch comprising an enclosing casing formed of an electrically insulating material, circuit controlling contacts arranged in one end wall of said casing, line contacts in the opposite end v wall of said casing, a control rod entering said casing through said one end wall, a contact on the end of said rod arranged to make butt contact with said line contacts and controlled by axial movement of said rod, an electrically insulating disc within said casing separating the circuit'controlling and'line contacts from each other, and having a keyconnection with said rod whereby'the disc is rotated by the rod and the rod can slide axially relative to said disc, a compression spring on said rod between the contact thereon and said disc biasing the disc toward said circuit contacts and the contact and rod toward said line contacts, contacts on said disc arranged to engage said circuit contacts selectively as said disc is rotated, and springs on said disc behind said contacts biasing them t0- ward said circuit contacts.

JACOB 'L SHROYER. I 

